| Multi-layer nano-particle preparation and applications -> Monitor Keywords |
|
|
 
Multi-layer nano-particle preparation and applicationsRelated Patent Categories: Synthetic Resins Or Natural Rubbers -- Part Of The Class 520 Series, Natural Rubber Compositions Having Nonreactive Materials (dnrm) Other Than: Carbon, Silicon Dioxide, Glass Titanium Dioxide, Water, Hydrocarbon, Halohydrocarbon, Ethylenically Unsaturated Reactant Admixed With A Preformed Reaction Product Derived From: (a) At Least One Polycarboxylic Acid, Ester, Or Anhydride; (b) At Least One Polyhydroxy Compound; And (c) At Least One Fatty Acid Glycerol Ester, Or A Fatty Acid Or Salt Derived From A Naturally Occurring Glyceride, Tall Oil, Or A Tall Oil Fatty Acid, At Least One Solid Polymer Derived From Ethylenic Reactants Only, Polymer Derived From Ethylenic Reactants Only Mixed With Ethylenic Reactant, Ethylenic Reactant Contains At Least Two Unsaturated Groups And Is Devoid Of An Aromatic Group, Block Copolymer Derived From Reactant Containing At Least Two Unsaturated Groups And Is Free Of An Aromatic GroupMulti-layer nano-particle preparation and applications description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070027264, Multi-layer nano-particle preparation and applications. Brief Patent Description - Full Patent Description - Patent Application Claims
Detailed Description of the Invention [0001] This application is a continuation application U.S. serial number 11/058,156 filed February 15, 2005, which is a divisional application of U.S. Serial Number 10/331,841 filed December 30, 2002 (now U.S. Patent No. 6,872,785), which is a continuation-in-part of U.S. Serial Number 10/223,393 filed August 19, 2002 (now U.S. Patent No. 6,956,084), which is a continuation-in-part of U.S. Serial Number 09/970,830 filed October 4, 2001 (now U.S. Patent 6,437,050) and U.S. Serial Number 10/038,748 filed December 31, 2001 (now U.S. Patent No. 6,689,469). BACKGROUND OF THE INVENTION [0002] The present invention relates to polymer nano-particles, methods for their preparation, and their use as, for example, additives for rubber, including natural and synthetic elastomers. The invention advantageously provides several mechanisms for surface modification, functionalization, and general characteristic tailoring to improve performance in rubbers, elastomers, and thermoplastics. [0003] Polymer nano-particles have attracted increased attention over the past several years in a variety of fields including catalysis, combinatorial chemistry, protein supports, magnets, and photonic crystals. Similarly, vinyl aromatic (e.g. polystyrene) microparticles have been prepared for uses as a reference standard in the calibration of various instruments, in medical research and in medical diagnostic tests. Such polystyrene microparticles have been prepared by anionic dispersion polymerization and emulsion polymerization. [0004] One benefit of using nano-particles as an additive in other materials is that they can be discrete particles uniformly dispersed throughout a host composition. Nano-particles preferably are monodisperse in size and uniform in shape. However, controlling the size of nano-particles during polymerization and/or the surface characteristics of such nano-particles can be difficult. Accordingly, achieving better control over the surface composition of such polymer nano-particles also is desirable. [0005] Rubbers may be advantageously modified by the addition of various polymer compositions. The physical properties of rubber moldability and tenacity are often improved through such modifications. Of course, however, the indiscriminate addition of nano-particles to rubber may cause degradation of the matrix material, i.e., the rubber, characteristics. Moreover, it is expected that primarily through the selection of nano-particles having suitable size, material composition, and surface chemistry, etc., will improve the matrix characteristics. [0006] In this regard, development of nano-particles having a surface layer which would be compatible with a wide variety of matrix materials is desirable because discrete particles could likely disperse more evenly throughout the host to provide a uniform matrix composition. However, the development of a process capable of reliably producing acceptable nano-particles has been a challenging endeavor. For example, the solubility of various monomers in traditional alkane solvents has made solution polymerization a difficult process by which to achieve nano-particles having tailored variety of surface layers. Moreover, the development of a solution polymerization process which produces reliable nano-particles, particularly nano-particles advantageously employed in rubber compositions, has been elusive. SUMMARY OF THE INVENTION [0007] A multi-layer nano-particle composition including a poly (alkenylbenzene) core and at least two additional layers is provided. The nano-particles have a mean average diameter less than about 100 nm. As used herein, the use of the phrase "additional layers" reflects, for example, layers formed of divergent monomers or of the same monomers but having differing characteristics including molecular weight, vinyl modification, functionalization, etc. As one effective usual characteristic of the present nano-particles, they can be described as onion-like in view of their multiple layers. [0008] A process for forming a multi-layer nano-particle is also provided. The process includes initiating the block copolymerization of a first monomer in a hydrocarbon solvent to form a living polymerization mixture. At least a second monomer is then added to the polymerization mixture and polymerized to form a living polymer chain. An alkenylbenzene monomer is also added to the polymerization mixture and allowed to polymerize onto the living polymer chain. The living polymer chains are made to aggregate to form micelles and at least one crosslinking agent is added to the polymerization mixture to form crosslinked nano-particles having a poly(alkenylbenzene) core and at least two additional layers. [0009] A rubber composition including an elastomer, nano-particles, carbon black, silica and a curing agent having low shrinkage properties is also provided. A process for preparing the rubber compound is similarly provided. Such compound shows its relatively high hysterisis, good tensile strength, good tear strength, strong resistance to creep, high temperature resistance, and good aging properties. A process of making the rubber compound for engine mount applications is similarly provided. [0010] Herein throughout, unless specifically stated otherwise: "vinyl-substituted aromatic hydrocarbon" and "alkenylbenzene" are used interchangeably; and "rubber" refers to rubber compounds, including natural rubber, and synthetic elastomers including styrene-butadiene rubber, ethylene propylene rubber, etc., which are known in the art. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIGURE 1 is a schematic depicting the principle of formation of multi-layer nano-particles. [0012] FIGURE 2 is a transmission electron microscopy (TEM) photograph of multi-layer nano-particles produced in accordance with EXAMPLE 1. [0013] FIGURE 3 is a TEM photograph of hydrogenated multi-layer nano-particles produced in accordance with EXAMPLE 2. [0014] FIGURE 4 is a TEM photograph of multi-layer nano-particles produced in accordance with EXAMPLE 3. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS [0015] GENERAL NANO-PARTICLE PROCESS OF FORMATION [0016] This application incorporates by reference U.S. Serial Numbers 09/970,830 filed October 4, 2001 (now U.S. Patent 6,437,050), 10/038,748 filed December 31, 2001 (now U.S. Patent No. 6,689,469), and 10/223,393 filed August 19, 2002 (now U.S. Patent No. 6,956,084). [0017] One exemplary polymer nano-particle of the present invention is formed from multiblock polymer chains having at least three blocks selected primarily from poly(conjugated diene) block and poly(alkenylbenzene) blocks. Of course, the various monomer constituents may be present to a limited extent in the blocks of another selected monomer. In addition, the present invention anticipates nano-particles wherein one or more layers are formed of a random copolymer of two or more monomer units. [0018] The poly(alkenylbenzene) blocks may be crosslinked to form the desired nanoparticles. The nano-particles have diameters--expressed as a mean average diameter--that are preferably less than about 100 nm, more preferably less than about 75 nm, and most preferably less than about 50 nm. The nano-particles preferably are substantially monodisperse and uniform in shape. The dispersity is represented by the ratio of M.sub.w to M.sub.n, with a ratio of 1 being substantially monodisperse. The polymer nano-particles of the present invention preferably have a dispersity less than about 1.3, more preferably less than about 1.2, and most preferably less than about 1.1. Moreover, the nano-particles are preferably spherical, though shape defects are acceptable, provided the nano-particles generally retain their discrete nature with little or no polymerization between particles. [0019] The nano-particles are preferably formed via dispersion polymerization, although emulsion polymerization is also contemplated. Hydrocarbons are preferably used as the dispersion solvent. Suitable solvents include aliphatic hydrocarbons, such as pentane, hexane, heptane, octane, nonane, decane, and the like, as well as alicyclic hydrocarbons, such as cyclohexane, methyl cyclopentane, cyclooctane, cyclopentane, cycloheptane, cyclononane, cyclodecane and the like. These hydrocarbons may be used individually or in combination. However, as more fully described herein below, selection of a solvent in which one polymer forming the nano-particles is more soluble than another polymer forming the nano-particles is important in micelle formation. Continue reading about Multi-layer nano-particle preparation and applications... Full patent description for Multi-layer nano-particle preparation and applications Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Multi-layer nano-particle preparation and applications patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Multi-layer nano-particle preparation and applications or other areas of interest. ### Previous Patent Application: Polymeric fibers and fabrics Next Patent Application: Process for producing rubbery polymer particle and process for producing resin composition containing the same Industry Class: Synthetic resins or natural rubbers -- part of the class 520 series ### FreshPatents.com Support Thank you for viewing the Multi-layer nano-particle preparation and applications patent info. IP-related news and info Results in 0.13456 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
